74ACT138SCX

Signal Switches, Multiplexers, Decoders Overview

The Fairchild Semiconductor 74ACT138SCX is a high-speed CMOS logic device belonging to the 74ACT series. It functions as a 3-line to 8-line inverting decoder or demultiplexer housed in a 16-pin SOIC surface-mount package. The component operates within a supply voltage range of 4.5V to 5.5V and supports an industrial operating temperature range from -40°C to +85°C. It features three enable inputs, including two active-low and one active-high, which facilitate system expansion without external inverters. The outputs are inverted and capable of sourcing and sinking currents up to 24mA.

Signal Switches, Multiplexers, Decoders Feature Summary

• Provides 3-to-8 line decoding with inverted outputs for memory addressing and data routing
• Includes three enable inputs (two active-low, one active-high) to simplify cascading and system expansion
• Features fully buffered inputs that present only one normalized load to the driving circuit
• Supports surface mount installation in a compact 16-SOIC package

Signal Switches, Multiplexers, Decoders Applications

• High-performance memory decoding systems
• Data transmission and routing applications
• Demultiplexing circuits requiring active-low output control

Signal Switches, Multiplexers, Decoders Procurement Notes

Verify the manufacturer designation carefully, as Fairchild Semiconductor's logic division was acquired by onsemi. Ensure the specific suffix matches the required packaging format, such as tape-and-reel quantities versus cut tape options. Confirm RoHS compliance status and moisture sensitivity level requirements against current project specifications before finalizing procurement orders.

Signal Switches, Multiplexers, Decoders Selection Notes

Select this component when a standard 3-to-8 decoder with inverted outputs is required for ACT-series logic compatibility. It is suitable for designs needing high fan-out capabilities due to its 24mA drive strength. Consider the package constraints of the 16-SOIC form factor and ensure the operating environment falls within the specified industrial temperature range.

Signal Switches, Multiplexers, Decoders Part Context

This part belongs to the widely adopted 74ACT family of logic integrated circuits, designed to bridge the performance gap between older TTL standards and newer AC/ACT technologies. The 74ACT138 variant specifically addresses the need for efficient address decoding in microprocessor-based systems. Its standardized pinout ensures compatibility with existing PCB layouts designed for similar decoder functions.

Signal Switches, Multiplexers, Decoders Replacement Considerations

Direct substitutes include the MC74ACT138DR2G manufactured by onsemi, which maintains functional equivalence. Other compatible alternatives may include devices from Texas Instruments such as the CD74ACT138ME4, provided the package type and electrical characteristics align with the original design requirements.